Limulus hemocyte transglutaminase. Its purification and characterization, and identification of the intracellular substrates.

摘要: To investigate further the molecular events of intracellular coagulation cascade in limulus hemocytes, a transglutaminase (TGase), which may be involved formation stabilized gel, was purified and characterized. Through purification procedures consisting six steps, 1.6 mg TGase with specific activity 940 amine incorporation unit/mg obtained from 32.4 g Tachypleus tridentatus hemocytes. The gave single band on SDS-polyacrylamide gel electrophoresis mass 86 kDa, demonstrated mammalian-type II TGase-like enzymatic properties. Ca(2+)-dependent inhibited by primary amines, EDTA, SH-reagents. Moreover, two major potential substrates for were identified hemocyte lysate using dansylcadaverine (DCA) presence 10 mM CaCl2 dithiothreitol. Of these protein substrates, an 80-kDa contained large number proline residues, amounting to about 22% total amino acids. On other hand, 8.6-kDa abundantly present hemocytes characterized as Cys-rich 81 acid residues calculated 8,671. entire sequence this established. Also, readily cross-linked intermolecularly TGase, forming multimers pentamers. We speculate that like plasma factor XIIIa, its play important role defense animal against invading microorganisms.